package com.java2104.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

//声明一个过滤器,需要实现javax.servlet.Filter
//@WebFilter(urlPatterns = {"/user/*"})//该过滤器将过滤以/user/开头的URI
public class LoginFilter  implements Filter{
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
//1.获取session对象
        HttpSession session=((HttpServletRequest)servletRequest).getSession();
//2.获取登录用户实例
        Object user=session.getAttribute("loginUser");
        if (user!=null){//如果已经登录过，则user不为空
            //在请求作用域中添加一个令牌
            servletRequest.setAttribute("token","Already login!"+System.currentTimeMillis());
            filterChain.doFilter(servletRequest,servletResponse);//请求放行

        }else{//user为null说明用户还未登录
            ((HttpServletResponse)servletResponse).sendRedirect("/login");//重定向登录页

        }

    }
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }



    @Override
    public void destroy() {

    }
}
